google2fa

# Google2FA ## Google Two-Factor Authentication for PHP Google2FA is a PHP implementation of the Google Two-Factor Authentication Module, supporting the HMAC-Based One-time Password (HOTP) algorithm specified in [RFC 4226](https://tools.ietf.org/html/rfc4226) and the Time-based One-time Password (TOTP) algorithm specified in [RFC 6238](https://tools.ietf.org/html/rfc6238). ---

--- ## Menu - [Version Compatibility](#version-compatibility) - [Version Support](#version-support) - [⚠️ Version 9.0.0 Breaking Change](#️-version-900-breaking-change) - [Google Two-Factor Authentication for PHP](#google-two-factor-authentication-for-php) - [Laravel bridge](#laravel-bridge) - [About QRCode generation](#about-qrcode-generation) - [Demos, Example & Playground](#demos-example--playground) - [Requirements](#requirements) - [Installing](#installing) - [Usage](#usage) - [How To Generate And Use Two Factor Authentication](#how-to-generate-and-use-two-factor-authentication) - [Generating QRCodes](#generating-qrcodes) - [QR Code Packages](#qr-code-packages) - [Examples of Usage](#examples-of-usage) - [HMAC Algorithms](#hmac-algorithms) - [Server Time](#server-time) - [Validation Window](#validation-window) - [Using a Bigger and Prefixing the Secret Key](#using-a-bigger-and-prefixing-the-secret-key) - [Google Authenticator secret key compatibility](#google-authenticator-secret-key-compatibility) - [Google Authenticator Apps](#google-authenticator-apps) - [Deprecation Warning](#deprecation-warning) - [Testing](#testing) - [Authors](#authors) - [License](#license) - [Contributing](#contributing) - [Sponsorships](#sponsorships) ## Version Compatibility PHP | Google2FA :--------|:---------- 7.4 | 8.x & 9.x 8.0 | 8.x & 9.x 8.1 | 8.x & 9.x 8.2 | 8.x & 9.x 8.3 | 8.x & 9.x 8.4 | 8.x & 9.x 8.5 | 8.x & 9.x 8.6 (beta) | CI-tested, not yet a supported target ## Version Support | Major | Status | What gets merged | | --------------- | --------------- | ---------------------------------------------------------------------- | | `9.x` | **Active** | New features, bug fixes, PHP/PHPUnit compatibility, dependency updates | | `8.x` | **Maintenance** | Security fixes and low-risk maintenance only (CI bumps, doc fixes) | | `7.x` and older | **Unsupported** | Please upgrade | When a new major is released, the previous major moves to *Maintenance*. The major before that becomes *Unsupported*. PHP version support roughly tracks [PHP's own support window](https://www.php.net/supported-versions.php). This table lists released majors only. Unreleased development branches (if any) aren't part of the support policy until they ship. For security vulnerabilities, see [SECURITY.md](SECURITY.md) — do **not** open a public issue. ## ⚠️ Version 9.0.0 Breaking Change ### Default Secret Key Length Increased **Version 9.0.0** introduces a **breaking change**: The default secret key length has been increased from **16 to 32 characters** for enhanced security. #### What Changed? - `generateSecretKey()` now generates 32-character secrets by default (previously 16) - This increases cryptographic entropy from 80 bits to 160 bits - Maintains full compatibility with Google Authenticator and other TOTP apps #### Migration Guide **If you want to keep the previous behavior (16-character secrets):** ```php // Old default behavior (v8.x and below) $secret = $google2fa->generateSecretKey(); // New way to get 16-character secrets (v9.0+) $secret = $google2fa->generateSecretKey(16); ``` **If you want to use the new default (32-character secrets):** ```php // This now generates 32-character secrets by default $secret = $google2fa->generateSecretKey(); ``` #### Potential Impact Areas - **Database schemas**: Check if your `google2fa_secret` columns can handle 32 characters - **Validation rules**: Update any length validations that expect exactly 16 characters - **Tests**: Update test assertions expecting 16-character secrets - **UI components**: Ensure QR code displays and secret key fields accommodate longer secrets **Important**: Existing 16-character secrets remain fully functional. Database updates are only needed if you want to use the new 32-character default behavior. #### Why This Change? While 16-character secrets meet RFC 6238 minimum requirements, 32-character secrets provide significantly better security: - **16 chars**: 80 bits of entropy (adequate but minimal) - **32 chars**: 160 bits of entropy (much stronger against brute force) This change aligns with modern security best practices for cryptographic applications. ## Laravel bridge This package is agnostic, but there's a [Laravel bridge](https://github.com/antonioribeiro/google2fa-laravel). ## About QRCode generation This package does not generate QRCodes for 2FA. If you are looking for Google Two-Factor Authentication, but also need to generate QRCode for it, you can use the [Google2FA QRCode package](https://github.com/antonioribeiro/google2fa-qrcode), which integrates this package and also generates QRCodes using the BaconQRCode library, or check options on how to do it yourself [here in the docs](#qr-code-packages). ## Demos, Example & Playground Please check the [Google2FA Package Playground](http://pragmarx.com/playground/google2fa). Here's a demo app showing how to use Google2FA: [google2fa-example](https://github.com/antonioribeiro/google2fa-example). ## Requirements - PHP 7.1 or greater ## Installing Use Composer to install it: composer require pragmarx/google2fa To generate inline QRCodes, you'll need to install a QR code generator, e.g. [BaconQrCode](https://github.com/Bacon/BaconQrCode): composer require bacon/bacon-qr-code ## Usage ### Instantiate it directly ```php use PragmaRX\Google2FA\Google2FA; $google2fa = new Google2FA(); return $google2fa->generateSecretKey(); ``` ## How To Generate And Use Two Factor Authentication Generate a secret key for your user and save it: ```php // Generates a 32-character secret key (v9.0.0+ default) $user->google2fa_secret = $google2fa->generateSecretKey(); // Or explicitly specify 16 characters for compatibility $user->google2fa_secret = $google2fa->generateSecretKey(16); ``` ## Generating QRCodes The more secure way of creating QRCode is to do it yourself or using a library. First you have to install a QR code generator e.g. BaconQrCode, as stated above, then you just have to generate the QR code url using: ```php $qrCodeUrl = $google2fa->getQRCodeUrl( $companyName, $companyEmail, $secretKey ); ``` Once you have the QR code url, you can feed it to your preferred QR code generator. ```php // Use your own QR Code generator to generate a data URL: $google2fa_url = custom_generate_qrcode_url($qrCodeUrl); /// and in your view: ``` And to verify, you just have to: ```php $secret = $request->input('secret'); $valid = $google2fa->verifyKey($user->google2fa_secret, $secret); ``` ## QR Code Packages This package suggests the use of [Bacon/QRCode](https://github.com/Bacon/BaconQrCode) because it is known as a good QR Code package, but you can use it with any other package, for instance [Google2FA QRCode](https://github.com/antonioribeiro/google2fa-qrcode), [Simple QrCode](https://www.simplesoftware.io/docs/simple-qrcode) or [Endroid QR Code](https://github.com/endroid/qr-code), all of them use [Bacon/QRCode](https://github.com/Bacon/BaconQrCode) to produce QR Codes. Usually you'll need a 2FA URL, so you just have to use the URL generator: ```php $google2fa->getQRCodeUrl($companyName, $companyEmail, $secretKey) ``` ## Examples of Usage ### [Google2FA QRCode](https://github.com/antonioribeiro/google2fa-qrcode) Get a QRCode to be used inline: ```php $google2fa = (new \PragmaRX\Google2FAQRCode\Google2FA()); $inlineUrl = $google2fa->getQRCodeInline( 'Company Name', '[email protected]', $google2fa->generateSecretKey() ); ``` And use in your template: ```php ``` ### [Simple QrCode](https://www.simplesoftware.io/docs/simple-qrcode) ```php ``` ### [Endroid QR Code Generator](https://github.com/endroid/qr-code) Generate the data URL ```php $qrCode = new \Endroid\QrCode\QrCode($value); $qrCode->setSize(100); $google2fa_url = $qrCode->writeDataUri(); ``` And in your view ```php ``` ### [Bacon/QRCode](https://github.com/Bacon/BaconQrCode) ```php getQRCodeUrl( 'pragmarx', '[email protected]', $google2fa->generateSecretKey() ); $writer = new Writer( new ImageRenderer( new RendererStyle(400), new ImagickImageBackEnd() ) ); $qrcode_image = base64_encode($writer->writeString($g2faUrl)); ``` And show it as an image: ```php "/> ``` ## HMAC Algorithms To comply with [RFC6238](https://tools.ietf.org/html/rfc6238), this package supports SHA1, SHA256 and SHA512. It defaults to SHA1, so to use a different algorithm you just have to use the method `setAlgorithm()`: ``` php use PragmaRX\Google2FA\Support\Constants; $google2fa->setAlgorithm(Constants::SHA512); ``` ## Server Time It's really important that you keep your server time in sync with some NTP server, on Ubuntu you can add this to the crontab: ```bash sudo service ntp stop sudo ntpd -gq sudo service ntp start ``` ## Validation Window To avoid problems with clocks that are slightly out of sync, we do not check against the current key only but also consider `$window` keys each from the past and future. You can pass `$window` as optional third parameter to `verifyKey`, it defaults to `1`. When a new key is generated every 30 seconds, then with the default setting, keys from one previous, the current, and one next 30-seconds intervals will be considered. To the user with properly synchronized clock, it will look like the key is valid for 60 seconds instead of 30, as the system will accept it even when it is already expired for let's say 29 seconds. ```php $secret = $request->input('secret'); $window = 8; // 8 keys (respectively 4 minutes) past and future $valid = $google2fa->verifyKey($user->google2fa_secret, $secret, $window); ``` Setting the `$window` parameter to `0` may also mean that the system will not accept a key that was valid when the user has seen it in their generator as it usually takes some time for the user to input the key to the particular form field. An attacker might be able to watch the user entering his credentials and one time key. Without further precautions, the key remains valid until it is no longer within the window of the server time. In order to prevent usage of a one time key that has already been used, you can utilize the `verifyKeyNewer` function. ```php $secret = $request->input('secret'); $timestamp = $google2fa->verifyKeyNewer($user->google2fa_secret, $secret, $user->google2fa_ts); if ($timestamp !== false) { $user->update(['google2fa_ts' => $timestamp]); // successful } else { // failed } ``` Note that `$timestamp` is either `false` (if the